As cameras become common household products, camera-based real-time monitoring gets more and more popular. When a user is not at home or sleeps, a camera may monitor an interior of a room in real time based on a scene change detection technology, and may trigger an alarm when detecting an abnormal scene change. The scene change detection technology determines the abnormal scene change by comparing an image currently acquired by the camera and a preset scene model. However, when an object not dangerous to the user, for example, a pet, moves in the room, the camera may determine the movement of the pet as an abnormal scene change and may trigger a false alarm. Therefore, it is important to improve the alarm method to avoid such false alarms.